Question

As per IUPAC rules, which one of the following groups will be regarded as the principal functional group?

• A. $-C\equiv C-$
• B. $-OH$
• C. $-CN$
• D. $-COOH$

Answer 1

The correct option is D $-COOH$

As per IUPAC rules, among the multiple substituents present in a molecule, -COOH is given the highest priority as aunctional group so as to consider all others as prefixes.
The order of priority for choosing the principal functional group among the given substituents is $-COOH>-CN>-OH>-C\equiv C-$